In a developing cartridge, the contact plate of the electrode member is disposed to contact the developing bias terminal within a plane of projection when a driven coupling part is projected in a first direction. A first axis line, which is an axis of the developing roller shaft, and a second axis line, which is an axis of the input gear, are disposed in parallel and equidistant in the front-rear direction. A part of the contact plate is disposed on the second axis line. A first line connecting an axis about which the input gear rotates and the developing roller shaft and a second line connecting the contact plate and the developing roller shaft are disposed parallel to each other. The distance between the first axis line and the second axis line equals the distance between the first axis line and the contact plate.